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We know: The maximum C-rate decreases with the increasing charging state.

Let's assume an 2 Ah Lithium-Ion or Lithium-Polymer mobile phone battery. (2 Ah is considered tiny in 2018, but this is just an example).

The internal charging current is 3 A (1.5 C) at 0% to 50% (couldn't it be higher at 0% than at 50%?)

At 50%, it starts decreasing, so it reaches 1C (which is 2A) at 75%.

Then it decreases from 1C to 0.1C throughout

My question is:
Does the same charging speed at a higher battery level (e.g. 75%) produce more heat and consume more lifespan, because it is closer to the maximum possbile C rate?

It is said to be unhealthy for a mobile phone battery to be charged to indicated 100% due to internal pressure.

Would this internal battery pressure also take effect if I charged the battery too quickly at a high level such as 85%?

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You lose 5 to 25% of the capacity from rapid charge depending on ESR (Equivalent Series Resistance) of the bigger internal capacitance that takes longer to charge which is responsible for short term “memory” after a pulse load or charge.

I^2ESR=Pd is the internal heat power generated from excessive current rates. Heat is an aggressive aging factor.

You can rush the charging at the expense of more rapid aging.

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    \$\begingroup\$ That means: If I disconnect after rapid charge, the battery quickly discharges a few percents? \$\endgroup\$ – neverMind9 Jul 14 '18 at 16:04
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    \$\begingroup\$ No it means if you dont slow down the rate the long time constant charge layer never quite fully charges up. "double electric effect" while the short time constant dielectric charge layer is done. There are 2 chemical layers effectively like two RC different caps in parallel \$\endgroup\$ – Sunnyskyguy EE75 Jul 14 '18 at 16:07
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    \$\begingroup\$ Where can I read about “double electric effect”? I do not quite understand what that is, \$\endgroup\$ – neverMind9 Jul 14 '18 at 16:14
  • \$\begingroup\$ in any search engine \$\endgroup\$ – Sunnyskyguy EE75 Jul 14 '18 at 17:56
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    \$\begingroup\$ "Electric Double Layer Effect" patents.google.com/patent/WO2016106501A1/en \$\endgroup\$ – Sunnyskyguy EE75 Jul 14 '18 at 19:51

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